Like the anarchist groups that dress in all black and attack people/infra/stores in the middle of the night during riot?

Its hard to say, because political violence is a spectrum and the border is very blurry between being an organized violent rioter and someone engaging in terroristic activities. Both are bad in their own way.

But fundamentally there doesn't seem to be a huge categorical/technical difference between violent rioting and "terroristic" activism other than that terroristic attacks are simply the more serious/worse version of political violence.

EX: Once it gets to the point of targeting actual critical infrastructure, we can call that terrorism, and just getting into a fist fight at a roudy protests wouldn't be (even though both are technically political violence).

That being said, serious riots can cause a lot of damage and even kill people, but the blame is more collectively spread out towards a large group of people, as opposed to a few small groups causing the large amount of damage.